This project directly addresses RFA-AI-06-005 request for technologies, strategies or models that contribute to new and more efficient ways of assessing and predicting microbicide acceptability within the preclinical framework of formulation development. Achieving this goal requires integration of behavioral with biophysical determinants of acceptability parameters. This project analyzes correspondence of cognitive and behavioral aspects of user ratings of microbicide characteristics and activity, with biophysical microbicide properties governing vaginal distribution/retention ("deployment") and hypothesized to correlate with human perceptions of microbicide use. During the R21 project, qualitative interviews, item development strategies and cognitive interviews will enable behavioral investigators to develop a user rating scale for use within the frameworkof preclinical feasibility studies of candidate microbicides. In parallel, formulation scientists will compute measures of biophysical functioning of 2 current over-the-counter vaginal gels, hypothesized to correlate with the behavioral constructs. Once it is shown that the behavioral tool (i.e., scale) has good psychometric characteristics, relationships between user rating measures and biophysical measures will be evaluated. Correspondence between what users can perceive/evaluate with respect to their experiences using a gel, and what biophysical properties/analysis can predict with respect to these perceptions and user ratings, will be delineated. The project goal is to demonstrate that these two measurement systems can be employed synergistically, toward optimization of 1) microbicide biophysical properties governing effective deployment and biofunctionality, and 2) user ratings of application- and vehicle-associated acceptability. In the R33 these measurement systems will be further evaluated and validated using novel GRAS gel formulations. Finally, a statistical framework that initiates prediction of user ratings of gels will be developed. The microbicide field's ability to co-determine microbicide function and acceptability will dramatically increase its ability to conceive and create optimal formulations in preclinical studies. By linking user ratings with biophysical properties, the resulting behavioral tool (scale) will better inform the preclinical microbicide pipeline, enabling products to be tailored to future users with greater certainty. In sum, this work will contribute methodology leading to rational design of microbicide formulations that co-optimize vaginal distribution and retention with user acceptability.